Mercurial > hg > graal-jvmci-8
annotate src/share/vm/opto/block.cpp @ 1685:0e35fa8ebccd
6973963: SEGV in ciBlock::start_bci() with EA
Summary: Added more checks into ResourceObj and growableArray to verify correctness of allocation type.
Reviewed-by: never, coleenp, dholmes
| author | kvn |
|---|---|
| date | Tue, 03 Aug 2010 15:55:03 -0700 |
| parents | c18cbe5936b8 |
| children | f95d63e2154a |
| rev | line source |
|---|---|
| 0 | 1 /* |
|
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2 * Copyright (c) 1997, 2009, Oracle and/or its affiliates. All rights reserved. |
| 0 | 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
| 4 * | |
| 5 * This code is free software; you can redistribute it and/or modify it | |
| 6 * under the terms of the GNU General Public License version 2 only, as | |
| 7 * published by the Free Software Foundation. | |
| 8 * | |
| 9 * This code is distributed in the hope that it will be useful, but WITHOUT | |
| 10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or | |
| 11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License | |
| 12 * version 2 for more details (a copy is included in the LICENSE file that | |
| 13 * accompanied this code). | |
| 14 * | |
| 15 * You should have received a copy of the GNU General Public License version | |
| 16 * 2 along with this work; if not, write to the Free Software Foundation, | |
| 17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. | |
| 18 * | |
|
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19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
|
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20 * or visit www.oracle.com if you need additional information or have any |
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21 * questions. |
| 0 | 22 * |
| 23 */ | |
| 24 | |
| 25 // Optimization - Graph Style | |
| 26 | |
| 27 #include "incls/_precompiled.incl" | |
| 28 #include "incls/_block.cpp.incl" | |
| 29 | |
| 30 | |
| 31 //----------------------------------------------------------------------------- | |
| 32 void Block_Array::grow( uint i ) { | |
| 33 assert(i >= Max(), "must be an overflow"); | |
| 34 debug_only(_limit = i+1); | |
| 35 if( i < _size ) return; | |
| 36 if( !_size ) { | |
| 37 _size = 1; | |
| 38 _blocks = (Block**)_arena->Amalloc( _size * sizeof(Block*) ); | |
| 39 _blocks[0] = NULL; | |
| 40 } | |
| 41 uint old = _size; | |
| 42 while( i >= _size ) _size <<= 1; // Double to fit | |
| 43 _blocks = (Block**)_arena->Arealloc( _blocks, old*sizeof(Block*),_size*sizeof(Block*)); | |
| 44 Copy::zero_to_bytes( &_blocks[old], (_size-old)*sizeof(Block*) ); | |
| 45 } | |
| 46 | |
| 47 //============================================================================= | |
| 48 void Block_List::remove(uint i) { | |
| 49 assert(i < _cnt, "index out of bounds"); | |
| 50 Copy::conjoint_words_to_lower((HeapWord*)&_blocks[i+1], (HeapWord*)&_blocks[i], ((_cnt-i-1)*sizeof(Block*))); | |
| 51 pop(); // shrink list by one block | |
| 52 } | |
| 53 | |
| 54 void Block_List::insert(uint i, Block *b) { | |
| 55 push(b); // grow list by one block | |
| 56 Copy::conjoint_words_to_higher((HeapWord*)&_blocks[i], (HeapWord*)&_blocks[i+1], ((_cnt-i-1)*sizeof(Block*))); | |
| 57 _blocks[i] = b; | |
| 58 } | |
| 59 | |
| 418 | 60 #ifndef PRODUCT |
| 61 void Block_List::print() { | |
| 62 for (uint i=0; i < size(); i++) { | |
| 63 tty->print("B%d ", _blocks[i]->_pre_order); | |
| 64 } | |
| 65 tty->print("size = %d\n", size()); | |
| 66 } | |
| 67 #endif | |
| 0 | 68 |
| 69 //============================================================================= | |
| 70 | |
| 71 uint Block::code_alignment() { | |
| 72 // Check for Root block | |
| 73 if( _pre_order == 0 ) return CodeEntryAlignment; | |
| 74 // Check for Start block | |
| 75 if( _pre_order == 1 ) return InteriorEntryAlignment; | |
| 76 // Check for loop alignment | |
| 418 | 77 if (has_loop_alignment()) return loop_alignment(); |
| 78 | |
| 79 return 1; // no particular alignment | |
| 80 } | |
| 81 | |
| 82 uint Block::compute_loop_alignment() { | |
| 0 | 83 Node *h = head(); |
| 84 if( h->is_Loop() && h->as_Loop()->is_inner_loop() ) { | |
| 85 // Pre- and post-loops have low trip count so do not bother with | |
| 86 // NOPs for align loop head. The constants are hidden from tuning | |
| 87 // but only because my "divide by 4" heuristic surely gets nearly | |
| 88 // all possible gain (a "do not align at all" heuristic has a | |
| 89 // chance of getting a really tiny gain). | |
| 90 if( h->is_CountedLoop() && (h->as_CountedLoop()->is_pre_loop() || | |
| 91 h->as_CountedLoop()->is_post_loop()) ) | |
| 92 return (OptoLoopAlignment > 4) ? (OptoLoopAlignment>>2) : 1; | |
| 93 // Loops with low backedge frequency should not be aligned. | |
| 94 Node *n = h->in(LoopNode::LoopBackControl)->in(0); | |
| 95 if( n->is_MachIf() && n->as_MachIf()->_prob < 0.01 ) { | |
| 96 return 1; // Loop does not loop, more often than not! | |
| 97 } | |
| 98 return OptoLoopAlignment; // Otherwise align loop head | |
| 99 } | |
| 418 | 100 |
| 0 | 101 return 1; // no particular alignment |
| 102 } | |
| 103 | |
| 104 //----------------------------------------------------------------------------- | |
| 105 // Compute the size of first 'inst_cnt' instructions in this block. | |
| 106 // Return the number of instructions left to compute if the block has | |
| 418 | 107 // less then 'inst_cnt' instructions. Stop, and return 0 if sum_size |
| 108 // exceeds OptoLoopAlignment. | |
| 0 | 109 uint Block::compute_first_inst_size(uint& sum_size, uint inst_cnt, |
| 110 PhaseRegAlloc* ra) { | |
| 111 uint last_inst = _nodes.size(); | |
| 112 for( uint j = 0; j < last_inst && inst_cnt > 0; j++ ) { | |
| 113 uint inst_size = _nodes[j]->size(ra); | |
| 114 if( inst_size > 0 ) { | |
| 115 inst_cnt--; | |
| 116 uint sz = sum_size + inst_size; | |
| 117 if( sz <= (uint)OptoLoopAlignment ) { | |
| 118 // Compute size of instructions which fit into fetch buffer only | |
| 119 // since all inst_cnt instructions will not fit even if we align them. | |
| 120 sum_size = sz; | |
| 121 } else { | |
| 122 return 0; | |
| 123 } | |
| 124 } | |
| 125 } | |
| 126 return inst_cnt; | |
| 127 } | |
| 128 | |
| 129 //----------------------------------------------------------------------------- | |
| 130 uint Block::find_node( const Node *n ) const { | |
| 131 for( uint i = 0; i < _nodes.size(); i++ ) { | |
| 132 if( _nodes[i] == n ) | |
| 133 return i; | |
| 134 } | |
| 135 ShouldNotReachHere(); | |
| 136 return 0; | |
| 137 } | |
| 138 | |
| 139 // Find and remove n from block list | |
| 140 void Block::find_remove( const Node *n ) { | |
| 141 _nodes.remove(find_node(n)); | |
| 142 } | |
| 143 | |
| 144 //------------------------------is_Empty--------------------------------------- | |
| 145 // Return empty status of a block. Empty blocks contain only the head, other | |
| 146 // ideal nodes, and an optional trailing goto. | |
| 147 int Block::is_Empty() const { | |
| 148 | |
| 149 // Root or start block is not considered empty | |
| 150 if (head()->is_Root() || head()->is_Start()) { | |
| 151 return not_empty; | |
| 152 } | |
| 153 | |
| 154 int success_result = completely_empty; | |
| 155 int end_idx = _nodes.size()-1; | |
| 156 | |
| 157 // Check for ending goto | |
| 158 if ((end_idx > 0) && (_nodes[end_idx]->is_Goto())) { | |
| 159 success_result = empty_with_goto; | |
| 160 end_idx--; | |
| 161 } | |
| 162 | |
| 163 // Unreachable blocks are considered empty | |
| 164 if (num_preds() <= 1) { | |
| 165 return success_result; | |
| 166 } | |
| 167 | |
| 168 // Ideal nodes are allowable in empty blocks: skip them Only MachNodes | |
| 169 // turn directly into code, because only MachNodes have non-trivial | |
| 170 // emit() functions. | |
| 171 while ((end_idx > 0) && !_nodes[end_idx]->is_Mach()) { | |
| 172 end_idx--; | |
| 173 } | |
| 174 | |
| 175 // No room for any interesting instructions? | |
| 176 if (end_idx == 0) { | |
| 177 return success_result; | |
| 178 } | |
| 179 | |
| 180 return not_empty; | |
| 181 } | |
| 182 | |
| 183 //------------------------------has_uncommon_code------------------------------ | |
| 605 | 184 // Return true if the block's code implies that it is likely to be |
| 0 | 185 // executed infrequently. Check to see if the block ends in a Halt or |
| 186 // a low probability call. | |
| 187 bool Block::has_uncommon_code() const { | |
| 188 Node* en = end(); | |
| 189 | |
| 190 if (en->is_Goto()) | |
| 191 en = en->in(0); | |
| 192 if (en->is_Catch()) | |
| 193 en = en->in(0); | |
| 194 if (en->is_Proj() && en->in(0)->is_MachCall()) { | |
| 195 MachCallNode* call = en->in(0)->as_MachCall(); | |
| 196 if (call->cnt() != COUNT_UNKNOWN && call->cnt() <= PROB_UNLIKELY_MAG(4)) { | |
| 197 // This is true for slow-path stubs like new_{instance,array}, | |
| 198 // slow_arraycopy, complete_monitor_locking, uncommon_trap. | |
| 199 // The magic number corresponds to the probability of an uncommon_trap, | |
| 200 // even though it is a count not a probability. | |
| 201 return true; | |
| 202 } | |
| 203 } | |
| 204 | |
| 205 int op = en->is_Mach() ? en->as_Mach()->ideal_Opcode() : en->Opcode(); | |
| 206 return op == Op_Halt; | |
| 207 } | |
| 208 | |
| 209 //------------------------------is_uncommon------------------------------------ | |
| 210 // True if block is low enough frequency or guarded by a test which | |
| 211 // mostly does not go here. | |
| 212 bool Block::is_uncommon( Block_Array &bbs ) const { | |
| 213 // Initial blocks must never be moved, so are never uncommon. | |
| 214 if (head()->is_Root() || head()->is_Start()) return false; | |
| 215 | |
| 216 // Check for way-low freq | |
| 217 if( _freq < BLOCK_FREQUENCY(0.00001f) ) return true; | |
| 218 | |
| 219 // Look for code shape indicating uncommon_trap or slow path | |
| 220 if (has_uncommon_code()) return true; | |
| 221 | |
| 222 const float epsilon = 0.05f; | |
| 223 const float guard_factor = PROB_UNLIKELY_MAG(4) / (1.f - epsilon); | |
| 224 uint uncommon_preds = 0; | |
| 225 uint freq_preds = 0; | |
| 226 uint uncommon_for_freq_preds = 0; | |
| 227 | |
| 228 for( uint i=1; i<num_preds(); i++ ) { | |
| 229 Block* guard = bbs[pred(i)->_idx]; | |
| 230 // Check to see if this block follows its guard 1 time out of 10000 | |
| 231 // or less. | |
| 232 // | |
| 233 // See list of magnitude-4 unlikely probabilities in cfgnode.hpp which | |
| 234 // we intend to be "uncommon", such as slow-path TLE allocation, | |
| 235 // predicted call failure, and uncommon trap triggers. | |
| 236 // | |
| 237 // Use an epsilon value of 5% to allow for variability in frequency | |
| 238 // predictions and floating point calculations. The net effect is | |
| 239 // that guard_factor is set to 9500. | |
| 240 // | |
| 241 // Ignore low-frequency blocks. | |
| 242 // The next check is (guard->_freq < 1.e-5 * 9500.). | |
| 243 if(guard->_freq*BLOCK_FREQUENCY(guard_factor) < BLOCK_FREQUENCY(0.00001f)) { | |
| 244 uncommon_preds++; | |
| 245 } else { | |
| 246 freq_preds++; | |
| 247 if( _freq < guard->_freq * guard_factor ) { | |
| 248 uncommon_for_freq_preds++; | |
| 249 } | |
| 250 } | |
| 251 } | |
| 252 if( num_preds() > 1 && | |
| 253 // The block is uncommon if all preds are uncommon or | |
| 254 (uncommon_preds == (num_preds()-1) || | |
| 255 // it is uncommon for all frequent preds. | |
| 256 uncommon_for_freq_preds == freq_preds) ) { | |
| 257 return true; | |
| 258 } | |
| 259 return false; | |
| 260 } | |
| 261 | |
| 262 //------------------------------dump------------------------------------------- | |
| 263 #ifndef PRODUCT | |
| 264 void Block::dump_bidx(const Block* orig) const { | |
| 265 if (_pre_order) tty->print("B%d",_pre_order); | |
| 266 else tty->print("N%d", head()->_idx); | |
| 267 | |
| 268 if (Verbose && orig != this) { | |
| 269 // Dump the original block's idx | |
| 270 tty->print(" ("); | |
| 271 orig->dump_bidx(orig); | |
| 272 tty->print(")"); | |
| 273 } | |
| 274 } | |
| 275 | |
| 276 void Block::dump_pred(const Block_Array *bbs, Block* orig) const { | |
| 277 if (is_connector()) { | |
| 278 for (uint i=1; i<num_preds(); i++) { | |
| 279 Block *p = ((*bbs)[pred(i)->_idx]); | |
| 280 p->dump_pred(bbs, orig); | |
| 281 } | |
| 282 } else { | |
| 283 dump_bidx(orig); | |
| 284 tty->print(" "); | |
| 285 } | |
| 286 } | |
| 287 | |
| 288 void Block::dump_head( const Block_Array *bbs ) const { | |
| 289 // Print the basic block | |
| 290 dump_bidx(this); | |
| 291 tty->print(": #\t"); | |
| 292 | |
| 293 // Print the incoming CFG edges and the outgoing CFG edges | |
| 294 for( uint i=0; i<_num_succs; i++ ) { | |
| 295 non_connector_successor(i)->dump_bidx(_succs[i]); | |
| 296 tty->print(" "); | |
| 297 } | |
| 298 tty->print("<- "); | |
| 299 if( head()->is_block_start() ) { | |
| 300 for (uint i=1; i<num_preds(); i++) { | |
| 301 Node *s = pred(i); | |
| 302 if (bbs) { | |
| 303 Block *p = (*bbs)[s->_idx]; | |
| 304 p->dump_pred(bbs, p); | |
| 305 } else { | |
| 306 while (!s->is_block_start()) | |
| 307 s = s->in(0); | |
| 308 tty->print("N%d ", s->_idx ); | |
| 309 } | |
| 310 } | |
| 311 } else | |
| 312 tty->print("BLOCK HEAD IS JUNK "); | |
| 313 | |
| 314 // Print loop, if any | |
| 315 const Block *bhead = this; // Head of self-loop | |
| 316 Node *bh = bhead->head(); | |
| 317 if( bbs && bh->is_Loop() && !head()->is_Root() ) { | |
| 318 LoopNode *loop = bh->as_Loop(); | |
| 319 const Block *bx = (*bbs)[loop->in(LoopNode::LoopBackControl)->_idx]; | |
| 320 while (bx->is_connector()) { | |
| 321 bx = (*bbs)[bx->pred(1)->_idx]; | |
| 322 } | |
| 323 tty->print("\tLoop: B%d-B%d ", bhead->_pre_order, bx->_pre_order); | |
| 324 // Dump any loop-specific bits, especially for CountedLoops. | |
| 325 loop->dump_spec(tty); | |
| 418 | 326 } else if (has_loop_alignment()) { |
| 327 tty->print(" top-of-loop"); | |
| 0 | 328 } |
| 329 tty->print(" Freq: %g",_freq); | |
| 330 if( Verbose || WizardMode ) { | |
| 331 tty->print(" IDom: %d/#%d", _idom ? _idom->_pre_order : 0, _dom_depth); | |
| 332 tty->print(" RegPressure: %d",_reg_pressure); | |
| 333 tty->print(" IHRP Index: %d",_ihrp_index); | |
| 334 tty->print(" FRegPressure: %d",_freg_pressure); | |
| 335 tty->print(" FHRP Index: %d",_fhrp_index); | |
| 336 } | |
| 337 tty->print_cr(""); | |
| 338 } | |
| 339 | |
| 340 void Block::dump() const { dump(0); } | |
| 341 | |
| 342 void Block::dump( const Block_Array *bbs ) const { | |
| 343 dump_head(bbs); | |
| 344 uint cnt = _nodes.size(); | |
| 345 for( uint i=0; i<cnt; i++ ) | |
| 346 _nodes[i]->dump(); | |
| 347 tty->print("\n"); | |
| 348 } | |
| 349 #endif | |
| 350 | |
| 351 //============================================================================= | |
| 352 //------------------------------PhaseCFG--------------------------------------- | |
| 353 PhaseCFG::PhaseCFG( Arena *a, RootNode *r, Matcher &m ) : | |
| 354 Phase(CFG), | |
| 355 _bbs(a), | |
| 1685 | 356 _root(r), |
| 357 _node_latency(NULL) | |
| 0 | 358 #ifndef PRODUCT |
| 359 , _trace_opto_pipelining(TraceOptoPipelining || C->method_has_option("TraceOptoPipelining")) | |
| 360 #endif | |
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361 #ifdef ASSERT |
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362 , _raw_oops(a) |
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363 #endif |
| 0 | 364 { |
| 365 ResourceMark rm; | |
| 366 // I'll need a few machine-specific GotoNodes. Make an Ideal GotoNode, | |
| 367 // then Match it into a machine-specific Node. Then clone the machine | |
| 368 // Node on demand. | |
| 369 Node *x = new (C, 1) GotoNode(NULL); | |
| 370 x->init_req(0, x); | |
| 371 _goto = m.match_tree(x); | |
| 372 assert(_goto != NULL, ""); | |
| 373 _goto->set_req(0,_goto); | |
| 374 | |
| 375 // Build the CFG in Reverse Post Order | |
| 376 _num_blocks = build_cfg(); | |
| 377 _broot = _bbs[_root->_idx]; | |
| 378 } | |
| 379 | |
| 380 //------------------------------build_cfg-------------------------------------- | |
| 381 // Build a proper looking CFG. Make every block begin with either a StartNode | |
| 382 // or a RegionNode. Make every block end with either a Goto, If or Return. | |
| 383 // The RootNode both starts and ends it's own block. Do this with a recursive | |
| 384 // backwards walk over the control edges. | |
| 385 uint PhaseCFG::build_cfg() { | |
| 386 Arena *a = Thread::current()->resource_area(); | |
| 387 VectorSet visited(a); | |
| 388 | |
| 389 // Allocate stack with enough space to avoid frequent realloc | |
| 390 Node_Stack nstack(a, C->unique() >> 1); | |
| 391 nstack.push(_root, 0); | |
| 392 uint sum = 0; // Counter for blocks | |
| 393 | |
| 394 while (nstack.is_nonempty()) { | |
| 395 // node and in's index from stack's top | |
| 396 // 'np' is _root (see above) or RegionNode, StartNode: we push on stack | |
| 397 // only nodes which point to the start of basic block (see below). | |
| 398 Node *np = nstack.node(); | |
| 399 // idx > 0, except for the first node (_root) pushed on stack | |
| 400 // at the beginning when idx == 0. | |
| 401 // We will use the condition (idx == 0) later to end the build. | |
| 402 uint idx = nstack.index(); | |
| 403 Node *proj = np->in(idx); | |
| 404 const Node *x = proj->is_block_proj(); | |
| 405 // Does the block end with a proper block-ending Node? One of Return, | |
| 406 // If or Goto? (This check should be done for visited nodes also). | |
| 407 if (x == NULL) { // Does not end right... | |
| 408 Node *g = _goto->clone(); // Force it to end in a Goto | |
| 409 g->set_req(0, proj); | |
| 410 np->set_req(idx, g); | |
| 411 x = proj = g; | |
| 412 } | |
| 413 if (!visited.test_set(x->_idx)) { // Visit this block once | |
| 414 // Skip any control-pinned middle'in stuff | |
| 415 Node *p = proj; | |
| 416 do { | |
| 417 proj = p; // Update pointer to last Control | |
| 418 p = p->in(0); // Move control forward | |
| 419 } while( !p->is_block_proj() && | |
| 420 !p->is_block_start() ); | |
| 421 // Make the block begin with one of Region or StartNode. | |
| 422 if( !p->is_block_start() ) { | |
| 423 RegionNode *r = new (C, 2) RegionNode( 2 ); | |
| 424 r->init_req(1, p); // Insert RegionNode in the way | |
| 425 proj->set_req(0, r); // Insert RegionNode in the way | |
| 426 p = r; | |
| 427 } | |
| 428 // 'p' now points to the start of this basic block | |
| 429 | |
| 430 // Put self in array of basic blocks | |
| 431 Block *bb = new (_bbs._arena) Block(_bbs._arena,p); | |
| 432 _bbs.map(p->_idx,bb); | |
| 433 _bbs.map(x->_idx,bb); | |
| 434 if( x != p ) // Only for root is x == p | |
| 435 bb->_nodes.push((Node*)x); | |
| 436 | |
| 437 // Now handle predecessors | |
| 438 ++sum; // Count 1 for self block | |
| 439 uint cnt = bb->num_preds(); | |
| 440 for (int i = (cnt - 1); i > 0; i-- ) { // For all predecessors | |
| 441 Node *prevproj = p->in(i); // Get prior input | |
| 442 assert( !prevproj->is_Con(), "dead input not removed" ); | |
| 443 // Check to see if p->in(i) is a "control-dependent" CFG edge - | |
| 444 // i.e., it splits at the source (via an IF or SWITCH) and merges | |
| 445 // at the destination (via a many-input Region). | |
| 446 // This breaks critical edges. The RegionNode to start the block | |
| 447 // will be added when <p,i> is pulled off the node stack | |
| 448 if ( cnt > 2 ) { // Merging many things? | |
| 449 assert( prevproj== bb->pred(i),""); | |
| 450 if(prevproj->is_block_proj() != prevproj) { // Control-dependent edge? | |
| 451 // Force a block on the control-dependent edge | |
| 452 Node *g = _goto->clone(); // Force it to end in a Goto | |
| 453 g->set_req(0,prevproj); | |
| 454 p->set_req(i,g); | |
| 455 } | |
| 456 } | |
| 457 nstack.push(p, i); // 'p' is RegionNode or StartNode | |
| 458 } | |
| 459 } else { // Post-processing visited nodes | |
| 460 nstack.pop(); // remove node from stack | |
| 461 // Check if it the fist node pushed on stack at the beginning. | |
| 462 if (idx == 0) break; // end of the build | |
| 463 // Find predecessor basic block | |
| 464 Block *pb = _bbs[x->_idx]; | |
| 465 // Insert into nodes array, if not already there | |
| 466 if( !_bbs.lookup(proj->_idx) ) { | |
| 467 assert( x != proj, "" ); | |
| 468 // Map basic block of projection | |
| 469 _bbs.map(proj->_idx,pb); | |
| 470 pb->_nodes.push(proj); | |
| 471 } | |
| 472 // Insert self as a child of my predecessor block | |
| 473 pb->_succs.map(pb->_num_succs++, _bbs[np->_idx]); | |
| 474 assert( pb->_nodes[ pb->_nodes.size() - pb->_num_succs ]->is_block_proj(), | |
| 475 "too many control users, not a CFG?" ); | |
| 476 } | |
| 477 } | |
| 478 // Return number of basic blocks for all children and self | |
| 479 return sum; | |
| 480 } | |
| 481 | |
| 482 //------------------------------insert_goto_at--------------------------------- | |
| 483 // Inserts a goto & corresponding basic block between | |
| 484 // block[block_no] and its succ_no'th successor block | |
| 485 void PhaseCFG::insert_goto_at(uint block_no, uint succ_no) { | |
| 486 // get block with block_no | |
| 487 assert(block_no < _num_blocks, "illegal block number"); | |
| 488 Block* in = _blocks[block_no]; | |
| 489 // get successor block succ_no | |
| 490 assert(succ_no < in->_num_succs, "illegal successor number"); | |
| 491 Block* out = in->_succs[succ_no]; | |
| 308 | 492 // Compute frequency of the new block. Do this before inserting |
| 493 // new block in case succ_prob() needs to infer the probability from | |
| 494 // surrounding blocks. | |
| 495 float freq = in->_freq * in->succ_prob(succ_no); | |
| 0 | 496 // get ProjNode corresponding to the succ_no'th successor of the in block |
| 497 ProjNode* proj = in->_nodes[in->_nodes.size() - in->_num_succs + succ_no]->as_Proj(); | |
| 498 // create region for basic block | |
| 499 RegionNode* region = new (C, 2) RegionNode(2); | |
| 500 region->init_req(1, proj); | |
| 501 // setup corresponding basic block | |
| 502 Block* block = new (_bbs._arena) Block(_bbs._arena, region); | |
| 503 _bbs.map(region->_idx, block); | |
| 504 C->regalloc()->set_bad(region->_idx); | |
| 505 // add a goto node | |
| 506 Node* gto = _goto->clone(); // get a new goto node | |
| 507 gto->set_req(0, region); | |
| 508 // add it to the basic block | |
| 509 block->_nodes.push(gto); | |
| 510 _bbs.map(gto->_idx, block); | |
| 511 C->regalloc()->set_bad(gto->_idx); | |
| 512 // hook up successor block | |
| 513 block->_succs.map(block->_num_succs++, out); | |
| 514 // remap successor's predecessors if necessary | |
| 515 for (uint i = 1; i < out->num_preds(); i++) { | |
| 516 if (out->pred(i) == proj) out->head()->set_req(i, gto); | |
| 517 } | |
| 518 // remap predecessor's successor to new block | |
| 519 in->_succs.map(succ_no, block); | |
| 308 | 520 // Set the frequency of the new block |
| 521 block->_freq = freq; | |
| 0 | 522 // add new basic block to basic block list |
| 523 _blocks.insert(block_no + 1, block); | |
| 524 _num_blocks++; | |
| 525 } | |
| 526 | |
| 527 //------------------------------no_flip_branch--------------------------------- | |
| 528 // Does this block end in a multiway branch that cannot have the default case | |
| 529 // flipped for another case? | |
| 530 static bool no_flip_branch( Block *b ) { | |
| 531 int branch_idx = b->_nodes.size() - b->_num_succs-1; | |
| 532 if( branch_idx < 1 ) return false; | |
| 533 Node *bra = b->_nodes[branch_idx]; | |
| 418 | 534 if( bra->is_Catch() ) |
| 535 return true; | |
| 0 | 536 if( bra->is_Mach() ) { |
| 418 | 537 if( bra->is_MachNullCheck() ) |
| 538 return true; | |
| 0 | 539 int iop = bra->as_Mach()->ideal_Opcode(); |
| 540 if( iop == Op_FastLock || iop == Op_FastUnlock ) | |
| 541 return true; | |
| 542 } | |
| 543 return false; | |
| 544 } | |
| 545 | |
| 546 //------------------------------convert_NeverBranch_to_Goto-------------------- | |
| 547 // Check for NeverBranch at block end. This needs to become a GOTO to the | |
| 548 // true target. NeverBranch are treated as a conditional branch that always | |
| 549 // goes the same direction for most of the optimizer and are used to give a | |
| 550 // fake exit path to infinite loops. At this late stage they need to turn | |
| 551 // into Goto's so that when you enter the infinite loop you indeed hang. | |
| 552 void PhaseCFG::convert_NeverBranch_to_Goto(Block *b) { | |
| 553 // Find true target | |
| 554 int end_idx = b->end_idx(); | |
| 555 int idx = b->_nodes[end_idx+1]->as_Proj()->_con; | |
| 556 Block *succ = b->_succs[idx]; | |
| 557 Node* gto = _goto->clone(); // get a new goto node | |
| 558 gto->set_req(0, b->head()); | |
| 559 Node *bp = b->_nodes[end_idx]; | |
| 560 b->_nodes.map(end_idx,gto); // Slam over NeverBranch | |
| 561 _bbs.map(gto->_idx, b); | |
| 562 C->regalloc()->set_bad(gto->_idx); | |
| 563 b->_nodes.pop(); // Yank projections | |
| 564 b->_nodes.pop(); // Yank projections | |
| 565 b->_succs.map(0,succ); // Map only successor | |
| 566 b->_num_succs = 1; | |
| 567 // remap successor's predecessors if necessary | |
| 568 uint j; | |
| 569 for( j = 1; j < succ->num_preds(); j++) | |
| 570 if( succ->pred(j)->in(0) == bp ) | |
| 571 succ->head()->set_req(j, gto); | |
| 572 // Kill alternate exit path | |
| 573 Block *dead = b->_succs[1-idx]; | |
| 574 for( j = 1; j < dead->num_preds(); j++) | |
| 575 if( dead->pred(j)->in(0) == bp ) | |
| 576 break; | |
| 577 // Scan through block, yanking dead path from | |
| 578 // all regions and phis. | |
| 579 dead->head()->del_req(j); | |
| 580 for( int k = 1; dead->_nodes[k]->is_Phi(); k++ ) | |
| 581 dead->_nodes[k]->del_req(j); | |
| 582 } | |
| 583 | |
| 418 | 584 //------------------------------move_to_next----------------------------------- |
| 0 | 585 // Helper function to move block bx to the slot following b_index. Return |
| 586 // true if the move is successful, otherwise false | |
| 418 | 587 bool PhaseCFG::move_to_next(Block* bx, uint b_index) { |
| 0 | 588 if (bx == NULL) return false; |
| 589 | |
| 590 // Return false if bx is already scheduled. | |
| 591 uint bx_index = bx->_pre_order; | |
| 592 if ((bx_index <= b_index) && (_blocks[bx_index] == bx)) { | |
| 593 return false; | |
| 594 } | |
| 595 | |
| 596 // Find the current index of block bx on the block list | |
| 597 bx_index = b_index + 1; | |
| 598 while( bx_index < _num_blocks && _blocks[bx_index] != bx ) bx_index++; | |
| 599 assert(_blocks[bx_index] == bx, "block not found"); | |
| 600 | |
| 601 // If the previous block conditionally falls into bx, return false, | |
| 602 // because moving bx will create an extra jump. | |
| 603 for(uint k = 1; k < bx->num_preds(); k++ ) { | |
| 604 Block* pred = _bbs[bx->pred(k)->_idx]; | |
| 605 if (pred == _blocks[bx_index-1]) { | |
| 606 if (pred->_num_succs != 1) { | |
| 607 return false; | |
| 608 } | |
| 609 } | |
| 610 } | |
| 611 | |
| 612 // Reinsert bx just past block 'b' | |
| 613 _blocks.remove(bx_index); | |
| 614 _blocks.insert(b_index + 1, bx); | |
| 615 return true; | |
| 616 } | |
| 617 | |
| 418 | 618 //------------------------------move_to_end------------------------------------ |
| 0 | 619 // Move empty and uncommon blocks to the end. |
| 418 | 620 void PhaseCFG::move_to_end(Block *b, uint i) { |
| 0 | 621 int e = b->is_Empty(); |
| 622 if (e != Block::not_empty) { | |
| 623 if (e == Block::empty_with_goto) { | |
| 624 // Remove the goto, but leave the block. | |
| 625 b->_nodes.pop(); | |
| 626 } | |
| 627 // Mark this block as a connector block, which will cause it to be | |
| 628 // ignored in certain functions such as non_connector_successor(). | |
| 629 b->set_connector(); | |
| 630 } | |
| 631 // Move the empty block to the end, and don't recheck. | |
| 632 _blocks.remove(i); | |
| 633 _blocks.push(b); | |
| 634 } | |
| 635 | |
| 418 | 636 //---------------------------set_loop_alignment-------------------------------- |
| 637 // Set loop alignment for every block | |
| 638 void PhaseCFG::set_loop_alignment() { | |
| 639 uint last = _num_blocks; | |
| 640 assert( _blocks[0] == _broot, "" ); | |
| 641 | |
| 642 for (uint i = 1; i < last; i++ ) { | |
| 643 Block *b = _blocks[i]; | |
| 644 if (b->head()->is_Loop()) { | |
| 645 b->set_loop_alignment(b); | |
| 646 } | |
| 647 } | |
| 648 } | |
| 649 | |
| 650 //-----------------------------remove_empty------------------------------------ | |
| 651 // Make empty basic blocks to be "connector" blocks, Move uncommon blocks | |
| 652 // to the end. | |
| 653 void PhaseCFG::remove_empty() { | |
| 0 | 654 // Move uncommon blocks to the end |
| 655 uint last = _num_blocks; | |
| 656 assert( _blocks[0] == _broot, "" ); | |
| 418 | 657 |
| 658 for (uint i = 1; i < last; i++) { | |
| 0 | 659 Block *b = _blocks[i]; |
| 418 | 660 if (b->is_connector()) break; |
| 0 | 661 |
| 662 // Check for NeverBranch at block end. This needs to become a GOTO to the | |
| 663 // true target. NeverBranch are treated as a conditional branch that | |
| 664 // always goes the same direction for most of the optimizer and are used | |
| 665 // to give a fake exit path to infinite loops. At this late stage they | |
| 666 // need to turn into Goto's so that when you enter the infinite loop you | |
| 667 // indeed hang. | |
| 668 if( b->_nodes[b->end_idx()]->Opcode() == Op_NeverBranch ) | |
| 669 convert_NeverBranch_to_Goto(b); | |
| 670 | |
| 671 // Look for uncommon blocks and move to end. | |
| 418 | 672 if (!C->do_freq_based_layout()) { |
| 673 if( b->is_uncommon(_bbs) ) { | |
| 674 move_to_end(b, i); | |
| 675 last--; // No longer check for being uncommon! | |
| 676 if( no_flip_branch(b) ) { // Fall-thru case must follow? | |
| 677 b = _blocks[i]; // Find the fall-thru block | |
| 678 move_to_end(b, i); | |
| 679 last--; | |
| 680 } | |
| 681 i--; // backup block counter post-increment | |
| 0 | 682 } |
| 683 } | |
| 684 } | |
| 685 | |
| 418 | 686 // Move empty blocks to the end |
| 0 | 687 last = _num_blocks; |
| 418 | 688 for (uint i = 1; i < last; i++) { |
| 0 | 689 Block *b = _blocks[i]; |
| 418 | 690 if (b->is_Empty() != Block::not_empty) { |
| 691 move_to_end(b, i); | |
| 692 last--; | |
| 693 i--; | |
| 0 | 694 } |
| 695 } // End of for all blocks | |
| 418 | 696 } |
| 0 | 697 |
| 418 | 698 //-----------------------------fixup_flow-------------------------------------- |
| 699 // Fix up the final control flow for basic blocks. | |
| 700 void PhaseCFG::fixup_flow() { | |
| 0 | 701 // Fixup final control flow for the blocks. Remove jump-to-next |
| 702 // block. If neither arm of a IF follows the conditional branch, we | |
| 703 // have to add a second jump after the conditional. We place the | |
| 704 // TRUE branch target in succs[0] for both GOTOs and IFs. | |
| 418 | 705 for (uint i=0; i < _num_blocks; i++) { |
| 0 | 706 Block *b = _blocks[i]; |
| 707 b->_pre_order = i; // turn pre-order into block-index | |
| 708 | |
| 709 // Connector blocks need no further processing. | |
| 710 if (b->is_connector()) { | |
| 711 assert((i+1) == _num_blocks || _blocks[i+1]->is_connector(), | |
| 712 "All connector blocks should sink to the end"); | |
| 713 continue; | |
| 714 } | |
| 715 assert(b->is_Empty() != Block::completely_empty, | |
| 716 "Empty blocks should be connectors"); | |
| 717 | |
| 718 Block *bnext = (i < _num_blocks-1) ? _blocks[i+1] : NULL; | |
| 719 Block *bs0 = b->non_connector_successor(0); | |
| 720 | |
| 721 // Check for multi-way branches where I cannot negate the test to | |
| 722 // exchange the true and false targets. | |
| 723 if( no_flip_branch( b ) ) { | |
| 724 // Find fall through case - if must fall into its target | |
| 725 int branch_idx = b->_nodes.size() - b->_num_succs; | |
| 726 for (uint j2 = 0; j2 < b->_num_succs; j2++) { | |
| 727 const ProjNode* p = b->_nodes[branch_idx + j2]->as_Proj(); | |
| 728 if (p->_con == 0) { | |
| 729 // successor j2 is fall through case | |
| 730 if (b->non_connector_successor(j2) != bnext) { | |
| 731 // but it is not the next block => insert a goto | |
| 732 insert_goto_at(i, j2); | |
| 733 } | |
| 734 // Put taken branch in slot 0 | |
| 735 if( j2 == 0 && b->_num_succs == 2) { | |
| 736 // Flip targets in succs map | |
| 737 Block *tbs0 = b->_succs[0]; | |
| 738 Block *tbs1 = b->_succs[1]; | |
| 739 b->_succs.map( 0, tbs1 ); | |
| 740 b->_succs.map( 1, tbs0 ); | |
| 741 } | |
| 742 break; | |
| 743 } | |
| 744 } | |
| 745 // Remove all CatchProjs | |
| 418 | 746 for (uint j1 = 0; j1 < b->_num_succs; j1++) b->_nodes.pop(); |
| 0 | 747 |
| 748 } else if (b->_num_succs == 1) { | |
| 749 // Block ends in a Goto? | |
| 750 if (bnext == bs0) { | |
| 751 // We fall into next block; remove the Goto | |
| 752 b->_nodes.pop(); | |
| 753 } | |
| 754 | |
| 755 } else if( b->_num_succs == 2 ) { // Block ends in a If? | |
| 756 // Get opcode of 1st projection (matches _succs[0]) | |
| 757 // Note: Since this basic block has 2 exits, the last 2 nodes must | |
| 758 // be projections (in any order), the 3rd last node must be | |
| 759 // the IfNode (we have excluded other 2-way exits such as | |
| 760 // CatchNodes already). | |
| 761 MachNode *iff = b->_nodes[b->_nodes.size()-3]->as_Mach(); | |
| 762 ProjNode *proj0 = b->_nodes[b->_nodes.size()-2]->as_Proj(); | |
| 763 ProjNode *proj1 = b->_nodes[b->_nodes.size()-1]->as_Proj(); | |
| 764 | |
| 765 // Assert that proj0 and succs[0] match up. Similarly for proj1 and succs[1]. | |
| 766 assert(proj0->raw_out(0) == b->_succs[0]->head(), "Mismatch successor 0"); | |
| 767 assert(proj1->raw_out(0) == b->_succs[1]->head(), "Mismatch successor 1"); | |
| 768 | |
| 769 Block *bs1 = b->non_connector_successor(1); | |
| 770 | |
| 771 // Check for neither successor block following the current | |
| 772 // block ending in a conditional. If so, move one of the | |
| 773 // successors after the current one, provided that the | |
| 774 // successor was previously unscheduled, but moveable | |
| 775 // (i.e., all paths to it involve a branch). | |
| 418 | 776 if( !C->do_freq_based_layout() && bnext != bs0 && bnext != bs1 ) { |
| 0 | 777 // Choose the more common successor based on the probability |
| 778 // of the conditional branch. | |
| 779 Block *bx = bs0; | |
| 780 Block *by = bs1; | |
| 781 | |
| 782 // _prob is the probability of taking the true path. Make | |
| 783 // p the probability of taking successor #1. | |
| 784 float p = iff->as_MachIf()->_prob; | |
| 785 if( proj0->Opcode() == Op_IfTrue ) { | |
| 786 p = 1.0 - p; | |
| 787 } | |
| 788 | |
| 789 // Prefer successor #1 if p > 0.5 | |
| 790 if (p > PROB_FAIR) { | |
| 791 bx = bs1; | |
| 792 by = bs0; | |
| 793 } | |
| 794 | |
| 795 // Attempt the more common successor first | |
| 418 | 796 if (move_to_next(bx, i)) { |
| 0 | 797 bnext = bx; |
| 418 | 798 } else if (move_to_next(by, i)) { |
| 0 | 799 bnext = by; |
| 800 } | |
| 801 } | |
| 802 | |
| 803 // Check for conditional branching the wrong way. Negate | |
| 804 // conditional, if needed, so it falls into the following block | |
| 805 // and branches to the not-following block. | |
| 806 | |
| 807 // Check for the next block being in succs[0]. We are going to branch | |
| 808 // to succs[0], so we want the fall-thru case as the next block in | |
| 809 // succs[1]. | |
| 810 if (bnext == bs0) { | |
| 811 // Fall-thru case in succs[0], so flip targets in succs map | |
| 812 Block *tbs0 = b->_succs[0]; | |
| 813 Block *tbs1 = b->_succs[1]; | |
| 814 b->_succs.map( 0, tbs1 ); | |
| 815 b->_succs.map( 1, tbs0 ); | |
| 816 // Flip projection for each target | |
| 817 { ProjNode *tmp = proj0; proj0 = proj1; proj1 = tmp; } | |
| 818 | |
| 418 | 819 } else if( bnext != bs1 ) { |
| 820 // Need a double-branch | |
| 0 | 821 // The existing conditional branch need not change. |
| 822 // Add a unconditional branch to the false target. | |
| 823 // Alas, it must appear in its own block and adding a | |
| 824 // block this late in the game is complicated. Sigh. | |
| 825 insert_goto_at(i, 1); | |
| 826 } | |
| 827 | |
| 828 // Make sure we TRUE branch to the target | |
| 418 | 829 if( proj0->Opcode() == Op_IfFalse ) { |
| 0 | 830 iff->negate(); |
| 418 | 831 } |
| 0 | 832 |
| 833 b->_nodes.pop(); // Remove IfFalse & IfTrue projections | |
| 834 b->_nodes.pop(); | |
| 835 | |
| 836 } else { | |
| 837 // Multi-exit block, e.g. a switch statement | |
| 838 // But we don't need to do anything here | |
| 839 } | |
| 840 } // End of for all blocks | |
| 841 } | |
| 842 | |
| 843 | |
| 844 //------------------------------dump------------------------------------------- | |
| 845 #ifndef PRODUCT | |
| 846 void PhaseCFG::_dump_cfg( const Node *end, VectorSet &visited ) const { | |
| 847 const Node *x = end->is_block_proj(); | |
| 848 assert( x, "not a CFG" ); | |
| 849 | |
| 850 // Do not visit this block again | |
| 851 if( visited.test_set(x->_idx) ) return; | |
| 852 | |
| 853 // Skip through this block | |
| 854 const Node *p = x; | |
| 855 do { | |
| 856 p = p->in(0); // Move control forward | |
| 857 assert( !p->is_block_proj() || p->is_Root(), "not a CFG" ); | |
| 858 } while( !p->is_block_start() ); | |
| 859 | |
| 860 // Recursively visit | |
| 861 for( uint i=1; i<p->req(); i++ ) | |
| 862 _dump_cfg(p->in(i),visited); | |
| 863 | |
| 864 // Dump the block | |
| 865 _bbs[p->_idx]->dump(&_bbs); | |
| 866 } | |
| 867 | |
| 868 void PhaseCFG::dump( ) const { | |
| 869 tty->print("\n--- CFG --- %d BBs\n",_num_blocks); | |
| 870 if( _blocks.size() ) { // Did we do basic-block layout? | |
| 871 for( uint i=0; i<_num_blocks; i++ ) | |
| 872 _blocks[i]->dump(&_bbs); | |
| 873 } else { // Else do it with a DFS | |
| 874 VectorSet visited(_bbs._arena); | |
| 875 _dump_cfg(_root,visited); | |
| 876 } | |
| 877 } | |
| 878 | |
| 879 void PhaseCFG::dump_headers() { | |
| 880 for( uint i = 0; i < _num_blocks; i++ ) { | |
| 881 if( _blocks[i] == NULL ) continue; | |
| 882 _blocks[i]->dump_head(&_bbs); | |
| 883 } | |
| 884 } | |
| 885 | |
| 886 void PhaseCFG::verify( ) const { | |
|
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887 #ifdef ASSERT |
| 0 | 888 // Verify sane CFG |
| 889 for( uint i = 0; i < _num_blocks; i++ ) { | |
| 890 Block *b = _blocks[i]; | |
| 891 uint cnt = b->_nodes.size(); | |
| 892 uint j; | |
| 893 for( j = 0; j < cnt; j++ ) { | |
| 894 Node *n = b->_nodes[j]; | |
| 895 assert( _bbs[n->_idx] == b, "" ); | |
| 896 if( j >= 1 && n->is_Mach() && | |
| 897 n->as_Mach()->ideal_Opcode() == Op_CreateEx ) { | |
| 898 assert( j == 1 || b->_nodes[j-1]->is_Phi(), | |
| 899 "CreateEx must be first instruction in block" ); | |
| 900 } | |
| 901 for( uint k = 0; k < n->req(); k++ ) { | |
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902 Node *def = n->in(k); |
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903 if( def && def != n ) { |
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904 assert( _bbs[def->_idx] || def->is_Con(), |
| 0 | 905 "must have block; constants for debug info ok" ); |
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906 // Verify that instructions in the block is in correct order. |
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907 // Uses must follow their definition if they are at the same block. |
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908 // Mostly done to check that MachSpillCopy nodes are placed correctly |
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909 // when CreateEx node is moved in build_ifg_physical(). |
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910 if( _bbs[def->_idx] == b && |
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911 !(b->head()->is_Loop() && n->is_Phi()) && |
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912 // See (+++) comment in reg_split.cpp |
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913 !(n->jvms() != NULL && n->jvms()->is_monitor_use(k)) ) { |
|
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914 bool is_loop = false; |
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915 if (n->is_Phi()) { |
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916 for( uint l = 1; l < def->req(); l++ ) { |
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917 if (n == def->in(l)) { |
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918 is_loop = true; |
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919 break; // Some kind of loop |
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920 } |
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921 } |
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922 } |
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923 assert( is_loop || b->find_node(def) < j, "uses must follow definitions" ); |
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566
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924 } |
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601
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925 if( def->is_SafePointScalarObject() ) { |
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926 assert(_bbs[def->_idx] == b, "SafePointScalarObject Node should be at the same block as its SafePoint node"); |
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927 assert(_bbs[def->_idx] == _bbs[def->in(0)->_idx], "SafePointScalarObject Node should be at the same block as its control edge"); |
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928 } |
| 0 | 929 } |
| 930 } | |
| 931 } | |
| 932 | |
| 933 j = b->end_idx(); | |
| 934 Node *bp = (Node*)b->_nodes[b->_nodes.size()-1]->is_block_proj(); | |
| 935 assert( bp, "last instruction must be a block proj" ); | |
| 936 assert( bp == b->_nodes[j], "wrong number of successors for this block" ); | |
| 937 if( bp->is_Catch() ) { | |
| 938 while( b->_nodes[--j]->Opcode() == Op_MachProj ) ; | |
| 939 assert( b->_nodes[j]->is_Call(), "CatchProj must follow call" ); | |
| 940 } | |
| 941 else if( bp->is_Mach() && bp->as_Mach()->ideal_Opcode() == Op_If ) { | |
| 942 assert( b->_num_succs == 2, "Conditional branch must have two targets"); | |
| 943 } | |
| 944 } | |
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945 #endif |
| 0 | 946 } |
| 947 #endif | |
| 948 | |
| 949 //============================================================================= | |
| 950 //------------------------------UnionFind-------------------------------------- | |
| 951 UnionFind::UnionFind( uint max ) : _cnt(max), _max(max), _indices(NEW_RESOURCE_ARRAY(uint,max)) { | |
| 952 Copy::zero_to_bytes( _indices, sizeof(uint)*max ); | |
| 953 } | |
| 954 | |
| 955 void UnionFind::extend( uint from_idx, uint to_idx ) { | |
| 956 _nesting.check(); | |
| 957 if( from_idx >= _max ) { | |
| 958 uint size = 16; | |
| 959 while( size <= from_idx ) size <<=1; | |
| 960 _indices = REALLOC_RESOURCE_ARRAY( uint, _indices, _max, size ); | |
| 961 _max = size; | |
| 962 } | |
| 963 while( _cnt <= from_idx ) _indices[_cnt++] = 0; | |
| 964 _indices[from_idx] = to_idx; | |
| 965 } | |
| 966 | |
| 967 void UnionFind::reset( uint max ) { | |
| 968 assert( max <= max_uint, "Must fit within uint" ); | |
| 969 // Force the Union-Find mapping to be at least this large | |
| 970 extend(max,0); | |
| 971 // Initialize to be the ID mapping. | |
| 418 | 972 for( uint i=0; i<max; i++ ) map(i,i); |
| 0 | 973 } |
| 974 | |
| 975 //------------------------------Find_compress---------------------------------- | |
| 976 // Straight out of Tarjan's union-find algorithm | |
| 977 uint UnionFind::Find_compress( uint idx ) { | |
| 978 uint cur = idx; | |
| 979 uint next = lookup(cur); | |
| 980 while( next != cur ) { // Scan chain of equivalences | |
| 981 assert( next < cur, "always union smaller" ); | |
| 982 cur = next; // until find a fixed-point | |
| 983 next = lookup(cur); | |
| 984 } | |
| 985 // Core of union-find algorithm: update chain of | |
| 986 // equivalences to be equal to the root. | |
| 987 while( idx != next ) { | |
| 988 uint tmp = lookup(idx); | |
| 989 map(idx, next); | |
| 990 idx = tmp; | |
| 991 } | |
| 992 return idx; | |
| 993 } | |
| 994 | |
| 995 //------------------------------Find_const------------------------------------- | |
| 996 // Like Find above, but no path compress, so bad asymptotic behavior | |
| 997 uint UnionFind::Find_const( uint idx ) const { | |
| 998 if( idx == 0 ) return idx; // Ignore the zero idx | |
| 999 // Off the end? This can happen during debugging dumps | |
| 1000 // when data structures have not finished being updated. | |
| 1001 if( idx >= _max ) return idx; | |
| 1002 uint next = lookup(idx); | |
| 1003 while( next != idx ) { // Scan chain of equivalences | |
| 1004 idx = next; // until find a fixed-point | |
| 1005 next = lookup(idx); | |
| 1006 } | |
| 1007 return next; | |
| 1008 } | |
| 1009 | |
| 1010 //------------------------------Union------------------------------------------ | |
| 1011 // union 2 sets together. | |
| 1012 void UnionFind::Union( uint idx1, uint idx2 ) { | |
| 1013 uint src = Find(idx1); | |
| 1014 uint dst = Find(idx2); | |
| 1015 assert( src, "" ); | |
| 1016 assert( dst, "" ); | |
| 1017 assert( src < _max, "oob" ); | |
| 1018 assert( dst < _max, "oob" ); | |
| 1019 assert( src < dst, "always union smaller" ); | |
| 1020 map(dst,src); | |
| 1021 } | |
| 418 | 1022 |
| 1023 #ifndef PRODUCT | |
| 1024 static void edge_dump(GrowableArray<CFGEdge *> *edges) { | |
| 1025 tty->print_cr("---- Edges ----"); | |
| 1026 for (int i = 0; i < edges->length(); i++) { | |
| 1027 CFGEdge *e = edges->at(i); | |
| 1028 if (e != NULL) { | |
| 1029 edges->at(i)->dump(); | |
| 1030 } | |
| 1031 } | |
| 1032 } | |
| 1033 | |
| 1034 static void trace_dump(Trace *traces[], int count) { | |
| 1035 tty->print_cr("---- Traces ----"); | |
| 1036 for (int i = 0; i < count; i++) { | |
| 1037 Trace *tr = traces[i]; | |
| 1038 if (tr != NULL) { | |
| 1039 tr->dump(); | |
| 1040 } | |
| 1041 } | |
| 1042 } | |
| 1043 | |
| 1044 void Trace::dump( ) const { | |
| 1045 tty->print_cr("Trace (freq %f)", first_block()->_freq); | |
| 1046 for (Block *b = first_block(); b != NULL; b = next(b)) { | |
| 1047 tty->print(" B%d", b->_pre_order); | |
| 1048 if (b->head()->is_Loop()) { | |
| 1049 tty->print(" (L%d)", b->compute_loop_alignment()); | |
| 1050 } | |
| 1051 if (b->has_loop_alignment()) { | |
| 1052 tty->print(" (T%d)", b->code_alignment()); | |
| 1053 } | |
| 1054 } | |
| 1055 tty->cr(); | |
| 1056 } | |
| 1057 | |
| 1058 void CFGEdge::dump( ) const { | |
| 1059 tty->print(" B%d --> B%d Freq: %f out:%3d%% in:%3d%% State: ", | |
| 1060 from()->_pre_order, to()->_pre_order, freq(), _from_pct, _to_pct); | |
| 1061 switch(state()) { | |
| 1062 case connected: | |
| 1063 tty->print("connected"); | |
| 1064 break; | |
| 1065 case open: | |
| 1066 tty->print("open"); | |
| 1067 break; | |
| 1068 case interior: | |
| 1069 tty->print("interior"); | |
| 1070 break; | |
| 1071 } | |
| 1072 if (infrequent()) { | |
| 1073 tty->print(" infrequent"); | |
| 1074 } | |
| 1075 tty->cr(); | |
| 1076 } | |
| 1077 #endif | |
| 1078 | |
| 1079 //============================================================================= | |
| 1080 | |
| 1081 //------------------------------edge_order------------------------------------- | |
| 1082 // Comparison function for edges | |
| 1083 static int edge_order(CFGEdge **e0, CFGEdge **e1) { | |
| 1084 float freq0 = (*e0)->freq(); | |
| 1085 float freq1 = (*e1)->freq(); | |
| 1086 if (freq0 != freq1) { | |
| 1087 return freq0 > freq1 ? -1 : 1; | |
| 1088 } | |
| 1089 | |
| 1090 int dist0 = (*e0)->to()->_rpo - (*e0)->from()->_rpo; | |
| 1091 int dist1 = (*e1)->to()->_rpo - (*e1)->from()->_rpo; | |
| 1092 | |
| 1093 return dist1 - dist0; | |
| 1094 } | |
| 1095 | |
| 1096 //------------------------------trace_frequency_order-------------------------- | |
| 1097 // Comparison function for edges | |
| 1098 static int trace_frequency_order(const void *p0, const void *p1) { | |
| 1099 Trace *tr0 = *(Trace **) p0; | |
| 1100 Trace *tr1 = *(Trace **) p1; | |
| 1101 Block *b0 = tr0->first_block(); | |
| 1102 Block *b1 = tr1->first_block(); | |
| 1103 | |
| 1104 // The trace of connector blocks goes at the end; | |
| 1105 // we only expect one such trace | |
| 1106 if (b0->is_connector() != b1->is_connector()) { | |
| 1107 return b1->is_connector() ? -1 : 1; | |
| 1108 } | |
| 1109 | |
| 1110 // Pull more frequently executed blocks to the beginning | |
| 1111 float freq0 = b0->_freq; | |
| 1112 float freq1 = b1->_freq; | |
| 1113 if (freq0 != freq1) { | |
| 1114 return freq0 > freq1 ? -1 : 1; | |
| 1115 } | |
| 1116 | |
| 1117 int diff = tr0->first_block()->_rpo - tr1->first_block()->_rpo; | |
| 1118 | |
| 1119 return diff; | |
| 1120 } | |
| 1121 | |
| 1122 //------------------------------find_edges------------------------------------- | |
| 1123 // Find edges of interest, i.e, those which can fall through. Presumes that | |
| 1124 // edges which don't fall through are of low frequency and can be generally | |
| 1125 // ignored. Initialize the list of traces. | |
| 1126 void PhaseBlockLayout::find_edges() | |
| 1127 { | |
| 1128 // Walk the blocks, creating edges and Traces | |
| 1129 uint i; | |
| 1130 Trace *tr = NULL; | |
| 1131 for (i = 0; i < _cfg._num_blocks; i++) { | |
| 1132 Block *b = _cfg._blocks[i]; | |
| 1133 tr = new Trace(b, next, prev); | |
| 1134 traces[tr->id()] = tr; | |
| 1135 | |
| 1136 // All connector blocks should be at the end of the list | |
| 1137 if (b->is_connector()) break; | |
| 1138 | |
| 1139 // If this block and the next one have a one-to-one successor | |
| 1140 // predecessor relationship, simply append the next block | |
| 1141 int nfallthru = b->num_fall_throughs(); | |
| 1142 while (nfallthru == 1 && | |
| 1143 b->succ_fall_through(0)) { | |
| 1144 Block *n = b->_succs[0]; | |
| 1145 | |
| 1146 // Skip over single-entry connector blocks, we don't want to | |
| 1147 // add them to the trace. | |
| 1148 while (n->is_connector() && n->num_preds() == 1) { | |
| 1149 n = n->_succs[0]; | |
| 1150 } | |
| 1151 | |
| 1152 // We see a merge point, so stop search for the next block | |
| 1153 if (n->num_preds() != 1) break; | |
| 1154 | |
| 1155 i++; | |
| 1156 assert(n = _cfg._blocks[i], "expecting next block"); | |
| 1157 tr->append(n); | |
| 1158 uf->map(n->_pre_order, tr->id()); | |
| 1159 traces[n->_pre_order] = NULL; | |
| 1160 nfallthru = b->num_fall_throughs(); | |
| 1161 b = n; | |
| 1162 } | |
| 1163 | |
| 1164 if (nfallthru > 0) { | |
| 1165 // Create a CFGEdge for each outgoing | |
| 1166 // edge that could be a fall-through. | |
| 1167 for (uint j = 0; j < b->_num_succs; j++ ) { | |
| 1168 if (b->succ_fall_through(j)) { | |
| 1169 Block *target = b->non_connector_successor(j); | |
| 1170 float freq = b->_freq * b->succ_prob(j); | |
| 1171 int from_pct = (int) ((100 * freq) / b->_freq); | |
| 1172 int to_pct = (int) ((100 * freq) / target->_freq); | |
| 1173 edges->append(new CFGEdge(b, target, freq, from_pct, to_pct)); | |
| 1174 } | |
| 1175 } | |
| 1176 } | |
| 1177 } | |
| 1178 | |
| 1179 // Group connector blocks into one trace | |
| 1180 for (i++; i < _cfg._num_blocks; i++) { | |
| 1181 Block *b = _cfg._blocks[i]; | |
| 1182 assert(b->is_connector(), "connector blocks at the end"); | |
| 1183 tr->append(b); | |
| 1184 uf->map(b->_pre_order, tr->id()); | |
| 1185 traces[b->_pre_order] = NULL; | |
| 1186 } | |
| 1187 } | |
| 1188 | |
| 1189 //------------------------------union_traces---------------------------------- | |
| 1190 // Union two traces together in uf, and null out the trace in the list | |
| 1191 void PhaseBlockLayout::union_traces(Trace* updated_trace, Trace* old_trace) | |
| 1192 { | |
| 1193 uint old_id = old_trace->id(); | |
| 1194 uint updated_id = updated_trace->id(); | |
| 1195 | |
| 1196 uint lo_id = updated_id; | |
| 1197 uint hi_id = old_id; | |
| 1198 | |
| 1199 // If from is greater than to, swap values to meet | |
| 1200 // UnionFind guarantee. | |
| 1201 if (updated_id > old_id) { | |
| 1202 lo_id = old_id; | |
| 1203 hi_id = updated_id; | |
| 1204 | |
| 1205 // Fix up the trace ids | |
| 1206 traces[lo_id] = traces[updated_id]; | |
| 1207 updated_trace->set_id(lo_id); | |
| 1208 } | |
| 1209 | |
| 1210 // Union the lower with the higher and remove the pointer | |
| 1211 // to the higher. | |
| 1212 uf->Union(lo_id, hi_id); | |
| 1213 traces[hi_id] = NULL; | |
| 1214 } | |
| 1215 | |
| 1216 //------------------------------grow_traces------------------------------------- | |
| 1217 // Append traces together via the most frequently executed edges | |
| 1218 void PhaseBlockLayout::grow_traces() | |
| 1219 { | |
| 1220 // Order the edges, and drive the growth of Traces via the most | |
| 1221 // frequently executed edges. | |
| 1222 edges->sort(edge_order); | |
| 1223 for (int i = 0; i < edges->length(); i++) { | |
| 1224 CFGEdge *e = edges->at(i); | |
| 1225 | |
| 1226 if (e->state() != CFGEdge::open) continue; | |
| 1227 | |
| 1228 Block *src_block = e->from(); | |
| 1229 Block *targ_block = e->to(); | |
| 1230 | |
| 1231 // Don't grow traces along backedges? | |
| 1232 if (!BlockLayoutRotateLoops) { | |
| 1233 if (targ_block->_rpo <= src_block->_rpo) { | |
| 1234 targ_block->set_loop_alignment(targ_block); | |
| 1235 continue; | |
| 1236 } | |
| 1237 } | |
| 1238 | |
| 1239 Trace *src_trace = trace(src_block); | |
| 1240 Trace *targ_trace = trace(targ_block); | |
| 1241 | |
| 1242 // If the edge in question can join two traces at their ends, | |
| 1243 // append one trace to the other. | |
| 1244 if (src_trace->last_block() == src_block) { | |
| 1245 if (src_trace == targ_trace) { | |
| 1246 e->set_state(CFGEdge::interior); | |
| 1247 if (targ_trace->backedge(e)) { | |
| 1248 // Reset i to catch any newly eligible edge | |
| 1249 // (Or we could remember the first "open" edge, and reset there) | |
| 1250 i = 0; | |
| 1251 } | |
| 1252 } else if (targ_trace->first_block() == targ_block) { | |
| 1253 e->set_state(CFGEdge::connected); | |
| 1254 src_trace->append(targ_trace); | |
| 1255 union_traces(src_trace, targ_trace); | |
| 1256 } | |
| 1257 } | |
| 1258 } | |
| 1259 } | |
| 1260 | |
| 1261 //------------------------------merge_traces----------------------------------- | |
| 1262 // Embed one trace into another, if the fork or join points are sufficiently | |
| 1263 // balanced. | |
| 1264 void PhaseBlockLayout::merge_traces(bool fall_thru_only) | |
| 1265 { | |
| 1266 // Walk the edge list a another time, looking at unprocessed edges. | |
| 1267 // Fold in diamonds | |
| 1268 for (int i = 0; i < edges->length(); i++) { | |
| 1269 CFGEdge *e = edges->at(i); | |
| 1270 | |
| 1271 if (e->state() != CFGEdge::open) continue; | |
| 1272 if (fall_thru_only) { | |
| 1273 if (e->infrequent()) continue; | |
| 1274 } | |
| 1275 | |
| 1276 Block *src_block = e->from(); | |
| 1277 Trace *src_trace = trace(src_block); | |
| 1278 bool src_at_tail = src_trace->last_block() == src_block; | |
| 1279 | |
| 1280 Block *targ_block = e->to(); | |
| 1281 Trace *targ_trace = trace(targ_block); | |
| 1282 bool targ_at_start = targ_trace->first_block() == targ_block; | |
| 1283 | |
| 1284 if (src_trace == targ_trace) { | |
| 1285 // This may be a loop, but we can't do much about it. | |
| 1286 e->set_state(CFGEdge::interior); | |
| 1287 continue; | |
| 1288 } | |
| 1289 | |
| 1290 if (fall_thru_only) { | |
| 1291 // If the edge links the middle of two traces, we can't do anything. | |
| 1292 // Mark the edge and continue. | |
| 1293 if (!src_at_tail & !targ_at_start) { | |
| 1294 continue; | |
| 1295 } | |
| 1296 | |
| 1297 // Don't grow traces along backedges? | |
| 1298 if (!BlockLayoutRotateLoops && (targ_block->_rpo <= src_block->_rpo)) { | |
| 1299 continue; | |
| 1300 } | |
| 1301 | |
| 1302 // If both ends of the edge are available, why didn't we handle it earlier? | |
| 1303 assert(src_at_tail ^ targ_at_start, "Should have caught this edge earlier."); | |
| 1304 | |
| 1305 if (targ_at_start) { | |
| 1306 // Insert the "targ" trace in the "src" trace if the insertion point | |
| 1307 // is a two way branch. | |
| 1308 // Better profitability check possible, but may not be worth it. | |
| 1309 // Someday, see if the this "fork" has an associated "join"; | |
| 1310 // then make a policy on merging this trace at the fork or join. | |
| 1311 // For example, other things being equal, it may be better to place this | |
| 1312 // trace at the join point if the "src" trace ends in a two-way, but | |
| 1313 // the insertion point is one-way. | |
| 1314 assert(src_block->num_fall_throughs() == 2, "unexpected diamond"); | |
| 1315 e->set_state(CFGEdge::connected); | |
| 1316 src_trace->insert_after(src_block, targ_trace); | |
| 1317 union_traces(src_trace, targ_trace); | |
| 1318 } else if (src_at_tail) { | |
| 1319 if (src_trace != trace(_cfg._broot)) { | |
| 1320 e->set_state(CFGEdge::connected); | |
| 1321 targ_trace->insert_before(targ_block, src_trace); | |
| 1322 union_traces(targ_trace, src_trace); | |
| 1323 } | |
| 1324 } | |
| 1325 } else if (e->state() == CFGEdge::open) { | |
| 1326 // Append traces, even without a fall-thru connection. | |
| 605 | 1327 // But leave root entry at the beginning of the block list. |
| 418 | 1328 if (targ_trace != trace(_cfg._broot)) { |
| 1329 e->set_state(CFGEdge::connected); | |
| 1330 src_trace->append(targ_trace); | |
| 1331 union_traces(src_trace, targ_trace); | |
| 1332 } | |
| 1333 } | |
| 1334 } | |
| 1335 } | |
| 1336 | |
| 1337 //----------------------------reorder_traces----------------------------------- | |
| 1338 // Order the sequence of the traces in some desirable way, and fixup the | |
| 1339 // jumps at the end of each block. | |
| 1340 void PhaseBlockLayout::reorder_traces(int count) | |
| 1341 { | |
| 1342 ResourceArea *area = Thread::current()->resource_area(); | |
| 1343 Trace ** new_traces = NEW_ARENA_ARRAY(area, Trace *, count); | |
| 1344 Block_List worklist; | |
| 1345 int new_count = 0; | |
| 1346 | |
| 1347 // Compact the traces. | |
| 1348 for (int i = 0; i < count; i++) { | |
| 1349 Trace *tr = traces[i]; | |
| 1350 if (tr != NULL) { | |
| 1351 new_traces[new_count++] = tr; | |
| 1352 } | |
| 1353 } | |
| 1354 | |
| 1355 // The entry block should be first on the new trace list. | |
| 1356 Trace *tr = trace(_cfg._broot); | |
| 1357 assert(tr == new_traces[0], "entry trace misplaced"); | |
| 1358 | |
| 1359 // Sort the new trace list by frequency | |
| 1360 qsort(new_traces + 1, new_count - 1, sizeof(new_traces[0]), trace_frequency_order); | |
| 1361 | |
| 1362 // Patch up the successor blocks | |
| 1363 _cfg._blocks.reset(); | |
| 1364 _cfg._num_blocks = 0; | |
| 1365 for (int i = 0; i < new_count; i++) { | |
| 1366 Trace *tr = new_traces[i]; | |
| 1367 if (tr != NULL) { | |
| 1368 tr->fixup_blocks(_cfg); | |
| 1369 } | |
| 1370 } | |
| 1371 } | |
| 1372 | |
| 1373 //------------------------------PhaseBlockLayout------------------------------- | |
| 1374 // Order basic blocks based on frequency | |
| 1375 PhaseBlockLayout::PhaseBlockLayout(PhaseCFG &cfg) : | |
| 1376 Phase(BlockLayout), | |
| 1377 _cfg(cfg) | |
| 1378 { | |
| 1379 ResourceMark rm; | |
| 1380 ResourceArea *area = Thread::current()->resource_area(); | |
| 1381 | |
| 1382 // List of traces | |
| 1383 int size = _cfg._num_blocks + 1; | |
| 1384 traces = NEW_ARENA_ARRAY(area, Trace *, size); | |
| 1385 memset(traces, 0, size*sizeof(Trace*)); | |
| 1386 next = NEW_ARENA_ARRAY(area, Block *, size); | |
| 1387 memset(next, 0, size*sizeof(Block *)); | |
| 1388 prev = NEW_ARENA_ARRAY(area, Block *, size); | |
| 1389 memset(prev , 0, size*sizeof(Block *)); | |
| 1390 | |
| 1391 // List of edges | |
| 1392 edges = new GrowableArray<CFGEdge*>; | |
| 1393 | |
| 1394 // Mapping block index --> block_trace | |
| 1395 uf = new UnionFind(size); | |
| 1396 uf->reset(size); | |
| 1397 | |
| 1398 // Find edges and create traces. | |
| 1399 find_edges(); | |
| 1400 | |
| 1401 // Grow traces at their ends via most frequent edges. | |
| 1402 grow_traces(); | |
| 1403 | |
| 1404 // Merge one trace into another, but only at fall-through points. | |
| 1405 // This may make diamonds and other related shapes in a trace. | |
| 1406 merge_traces(true); | |
| 1407 | |
| 1408 // Run merge again, allowing two traces to be catenated, even if | |
| 1409 // one does not fall through into the other. This appends loosely | |
| 1410 // related traces to be near each other. | |
| 1411 merge_traces(false); | |
| 1412 | |
| 1413 // Re-order all the remaining traces by frequency | |
| 1414 reorder_traces(size); | |
| 1415 | |
| 1416 assert(_cfg._num_blocks >= (uint) (size - 1), "number of blocks can not shrink"); | |
| 1417 } | |
| 1418 | |
| 1419 | |
| 1420 //------------------------------backedge--------------------------------------- | |
| 1421 // Edge e completes a loop in a trace. If the target block is head of the | |
| 1422 // loop, rotate the loop block so that the loop ends in a conditional branch. | |
| 1423 bool Trace::backedge(CFGEdge *e) { | |
| 1424 bool loop_rotated = false; | |
| 1425 Block *src_block = e->from(); | |
| 1426 Block *targ_block = e->to(); | |
| 1427 | |
| 1428 assert(last_block() == src_block, "loop discovery at back branch"); | |
| 1429 if (first_block() == targ_block) { | |
| 1430 if (BlockLayoutRotateLoops && last_block()->num_fall_throughs() < 2) { | |
| 1431 // Find the last block in the trace that has a conditional | |
| 1432 // branch. | |
| 1433 Block *b; | |
| 1434 for (b = last_block(); b != NULL; b = prev(b)) { | |
| 1435 if (b->num_fall_throughs() == 2) { | |
| 1436 break; | |
| 1437 } | |
| 1438 } | |
| 1439 | |
| 1440 if (b != last_block() && b != NULL) { | |
| 1441 loop_rotated = true; | |
| 1442 | |
| 1443 // Rotate the loop by doing two-part linked-list surgery. | |
| 1444 append(first_block()); | |
| 1445 break_loop_after(b); | |
| 1446 } | |
| 1447 } | |
| 1448 | |
| 1449 // Backbranch to the top of a trace | |
| 605 | 1450 // Scroll forward through the trace from the targ_block. If we find |
| 418 | 1451 // a loop head before another loop top, use the the loop head alignment. |
| 1452 for (Block *b = targ_block; b != NULL; b = next(b)) { | |
| 1453 if (b->has_loop_alignment()) { | |
| 1454 break; | |
| 1455 } | |
| 1456 if (b->head()->is_Loop()) { | |
| 1457 targ_block = b; | |
| 1458 break; | |
| 1459 } | |
| 1460 } | |
| 1461 | |
| 1462 first_block()->set_loop_alignment(targ_block); | |
| 1463 | |
| 1464 } else { | |
| 1465 // Backbranch into the middle of a trace | |
| 1466 targ_block->set_loop_alignment(targ_block); | |
| 1467 } | |
| 1468 | |
| 1469 return loop_rotated; | |
| 1470 } | |
| 1471 | |
| 1472 //------------------------------fixup_blocks----------------------------------- | |
| 1473 // push blocks onto the CFG list | |
| 1474 // ensure that blocks have the correct two-way branch sense | |
| 1475 void Trace::fixup_blocks(PhaseCFG &cfg) { | |
| 1476 Block *last = last_block(); | |
| 1477 for (Block *b = first_block(); b != NULL; b = next(b)) { | |
| 1478 cfg._blocks.push(b); | |
| 1479 cfg._num_blocks++; | |
| 1480 if (!b->is_connector()) { | |
| 1481 int nfallthru = b->num_fall_throughs(); | |
| 1482 if (b != last) { | |
| 1483 if (nfallthru == 2) { | |
| 1484 // Ensure that the sense of the branch is correct | |
| 1485 Block *bnext = next(b); | |
| 1486 Block *bs0 = b->non_connector_successor(0); | |
| 1487 | |
| 1488 MachNode *iff = b->_nodes[b->_nodes.size()-3]->as_Mach(); | |
| 1489 ProjNode *proj0 = b->_nodes[b->_nodes.size()-2]->as_Proj(); | |
| 1490 ProjNode *proj1 = b->_nodes[b->_nodes.size()-1]->as_Proj(); | |
| 1491 | |
| 1492 if (bnext == bs0) { | |
| 1493 // Fall-thru case in succs[0], should be in succs[1] | |
| 1494 | |
| 1495 // Flip targets in _succs map | |
| 1496 Block *tbs0 = b->_succs[0]; | |
| 1497 Block *tbs1 = b->_succs[1]; | |
| 1498 b->_succs.map( 0, tbs1 ); | |
| 1499 b->_succs.map( 1, tbs0 ); | |
| 1500 | |
| 1501 // Flip projections to match targets | |
| 1502 b->_nodes.map(b->_nodes.size()-2, proj1); | |
| 1503 b->_nodes.map(b->_nodes.size()-1, proj0); | |
| 1504 } | |
| 1505 } | |
| 1506 } | |
| 1507 } | |
| 1508 } | |
| 1509 } |